The latest models of meteors and meteoroid streams, the first science results from the November Leonid meteor storm and the latest Mars research will be presented at the fall American Geophysical Union (AGU) meeting Dec. 10 through 14 at the Moscone Convention Center in San Francisco.

Dr. Peter Jenniskens, principal investigator of NASA's Leonid "MAC" mission, which tracked the meteors, will present the latest data at a special session, "The 2001 and 2002 Leonid Meteor Storms," at the AGU meeting at 1:30 p.m. PST, Dec. 11 in the Moscone Center's room MC 120. Jenniskens, together with scientists from the Scripps Institute and Cornell University, will discuss first results from the last two Leonid meteor events, including airborne meteor and meteor train observations, comet dust composition, the fate of organic matter at the time of the origin of life, and the physics and chemistry of the Earth's upper atmosphere. Approximately 30 NASA Ames scientists will participate in a wide range of space and planetary science presentations at the AGU meeting, either as session chairs, invited speakers, lead authors or 'poster session' presenters.

There will be more than 14 AGU presentations dealing with NASA's latest Mars research, with discussions ranging from the accuracy of Mars climate models to what currently is known about the red planet's surface geology. Ames scientists Dr Robert Haberle and Dr Anthony Colaprete will present work about Mars' climate on Wednesday and Thursday. The Mars Global Surveyor (MGS) mission has provided a wealth of new data bearing directly on Mars' climate. Colaprete, Haberle and others will compare the most recent MGS data with data from the NASA Ames Mars General Circulation Model at separate sessions scheduled for Dec. 12 at 8:30 a.m. (MC 308) and 3:30 p.m. PST (MC Hall D) and Dec. 13 at 8:30 a.m. PST (MC Hall D). Ames climate researcher Dr. Jeffery Hollingsworth will discuss Mars' atmospheric circulation in the Hellas impact basin, comparing model simulations with recently acquired MGS data on Dec. 12 at 3:55 p.m. PST in MC 301.

Also on the Mars theme, Ames' Dr. Nathalie Cabrol will present a new paper, "From Gullies to Glaciers: A Continuum of Evidence Supporting A Recent Climate Change on Mars," on Dec. 10 at 4:20 p.m. PST in MC 131. Based on the recent discovery of pristine martian gullies by the Mars Global Surveyor, Cabrol will present a continuum of evidence that supports a recent climate change on Mars, signaling a more recent hydrologically active Mars than scientists had thought previously. Her talk is part of the "New Paradigms for the Water Cycle on Mars I" session that begins at 1:30 p.m. PST.

Conditions on early Earth are another topic well represented by Ames scientists. Dr. Kevin Zahnle of Ames will deliver two review talks discussing the earliest atmosphere of the Earth. He will present "Hot Steam, Hard Rain and Icy Wastes in the Hadean" on Dec. 11 at 8:30 a.m. PST in MC 308 at the 'Follow the Water' session and "The Hadean Atmosphere (When Impacts Ruled the Earth)" on Dec. 14 at 11:10 a.m. PST in MC 134 in the 'Origin and Early Evolution of the Earth' session.

The 'Follow the Water' session focuses on the search for habitable environments in the solar system. It will be co-chaired by Dr. Michael Meyer, senior scientist for astrobiology in the Office of Space Science at NASA Headquarters and by Dr. Jack Farmer, principal investigator of the Arizona State University research team at the NASA Astrobiology Institute.

Ames researchers Dr. Linda Jahnke and Kenneth Cullings will reconstruct the biomarker record of early Earth in a poster sesion (B22D-0184) at 1:30 p.m PST on Dec. 11 in MC Hall D.

For further information about Ames' participation in the AGU, go to the AGU website and search the 'Meeting at a Glance' section using the researcher's e-mail address. You also can use the keyword 'arc.nasa.gov' to locate abstracts and session information.

To arrange interviews at AGU, please contact Harvey Leifert in the AGU Press Room, MC 111, 415/905-1007. Reporters also may arrange an interview at AGU by using the AGU message board located outside Moscone's main exhibition hall.

The AGU is a worldwide organization comprising over 39,000 scientists in Earth and space science, publishing more than a dozen peer-reviewed journals annually and holding regular science meetings.